Tablet and Display
Tablet mode: the iPad is a blank drawing surface and you look at your Mac. Display mode: the iPad shows your Mac screen, mirrored or extended, with the same tablet features on top.
Screen Recording
Display mode needs Screen Recording on the Mac, asked the first time you use it. You can change it in System Settings › Privacy & Security. If you turn it off, DeusPen pauses Display mode and tells you what is missing.
In Display mode, the companion captures the display you choose and sends it to your iPad over the same local connection. It is never recorded, stored or uploaded.
Related
Still stuck? Email support@deuspen.com with your iPad and computer models, the app you draw in, whether you were on the cable or Wi-Fi, and what you expected. The Diagnostics panel in the companion's Settings shows the connection state in words; tell us what it says.